question_answer

Values for Brewsters angle can be

A)  only less than \[45{}^\circ \]

B)  only greater than\[45{}^\circ \]

C)  any value in the range\[0{}^\circ \]to\[90{}^\circ \]except\[45{}^\circ \]

D)  any value in the range\[0{}^\circ \]to\[90{}^\circ \]including\[45{}^\circ \]

Correct Answer: C

Solution :

 Brewsters angle corresponding to two media of refractive indices\[{{r}_{1}}\]and\[{{r}_{2}}\]is \[\tan {{i}_{B}}=\left( \frac{{{n}_{2}}}{{{n}_{1}}} \right)\] where,\[{{n}_{2}}\]is refractive index of denser medium and\[{{n}_{1}}\]is refractive index of rarer medium. If two mediums are same, i.e. \[{{n}_{1}}={{n}_{2}}\Rightarrow \tan {{i}_{B}}=1\]or\[{{i}_{B}}=45{}^\circ \] Polarisation is not possible if two mediums are same. Therefore\[{{i}_{B}}\ne 45{}^\circ \] Hence, Brewsters angle can have any value in the range\[0{}^\circ \]to\[90{}^\circ \]except\[45{}^\circ \].